Energy based devices and methods for treatment of patent foramen ovale

ABSTRACT

Methods, devices and systems for treating patent foramen ovale (PFO) involve advancing a catheter device to a position in a heart for treating a PFO, bringing tissues adjacent the PFO at least partially together, and applying energy to the tissues to substantially close the PFO acutely. Catheter devices generally include an elongate catheter body, at least one tissue apposition member at or near the distal end for bringing the tissues together, and at least one energy transmission member at or near the distal end for applying energy to the tissues. In some embodiments, the tissue apposition member(s) also act as the energy transmission member(s). Applied energy may be monoploar or bipolar radiofrequency energy or any other suitable energy, such as laser, microwave, ultrasound, resistive heating or the like.

CROSS-REFERENCES TO RELATED APPLICATIONS

This application is a divisional of U.S. Patent Application No.10/787,532 (Attorney Docket No. 022128-000130US), filed Feb. 25, 2004which claims priority to U.S. Provisional Patent Application Nos.60/458,854 (Attorney Docket No. 022128-000100US, formerly20979-002100US), filed on Mar. 27, 2003; Ser. No. 60/478,035 (AttorneyDocket No. 022128-000110US, formerly 20979-002110US), filed on Jun. 11,2003, and Ser. No. 60/490,082 (Attorney Docket No. 022128-000120US,formerly 20979-002120US), filed on Jul. 24, 2003, the full disclosuresof which are incorporated herein by reference. This application isrelated to U.S. patent application Ser. Nos. 10/665,974 (Attorney DocketNo. 022128-000300US, formerly 20979-002600US), filed on Sep. 18, 2003,and Ser. No. 10/679,245 (Attorney Docket No. 022128-000200US, formerly20979-002500US), filed on Oct. 2, 2003, the full disclosures of whichare incorporated herein by reference.

BACKGROUND OF THE INVENTION

The invention generally relates to medical devices and methods. Morespecifically, the invention relates to energy based devices, systems andmethods for treatment of patent foramen ovale.

Fetal blood circulation is much different than adult circulation.Because fetal blood is oxygenated by the placenta, rather than the fetallungs, blood is generally shunted away from the lungs to the peripheraltissues through a number of vessels and foramens that remain patent(i.e., open) during fetal life and typically close shortly after birth.For example, fetal blood passes directly from the right atrium throughthe foramen ovale into the left atrium, and a portion of bloodcirculating through the pulmonary artery trunk passes through the ductusarteriosus to the aorta. This fetal circulation is shown in attachedFIG. 1.

At birth, as a newborn begins breathing, blood pressure in the leftatrium rises above the pressure in the right atrium. In most newborns, aflap of tissue closes the foramen ovale and heals together. Inapproximately 20,000 babies born each year in the US, the flap of tissueis missing, and the hole remains open as an atrial septal defect (ASD).In a much more significant percentage of the population (estimates rangefrom 5% to 20% of the entire population), the flap is present but doesnot heal together. This condition is known as a patent foramen ovale(PFO). Whenever the pressure in the right atrium rises above that in theleft atrium, blood pressure can push this patent channel open, allowingblood to flow from the right atrium to the left atrium.

Patent foramen ovale has long been considered a relatively benigncondition, since it typically has little effect on the body'scirculation. More recently, however, it has been found that asignificant number of strokes may be caused at least in part by PFO. Insome cases, stroke may occur because a PFO allows blood containing smallthrombi to flow directly from the venous circulation to the arterialcirculation and into the brain, rather than flowing to the lungs wherethe thrombi can become trapped and gradually dissolved. In other cases,thrombi might form in the patent channel of the PFO itself and becomedislodged when the pressures cause blood to flow from the right atriumto the left atrium. It has been estimated that patients with PFOs whohave already had cryptogenic strokes have a 4% risk per year of havinganother stroke.

Further research is currently being conducted into the link between PFOand stroke. At the present time, if someone with a PFO has two or morestrokes, the healthcare system in the U.S. may reimburse a surgical orother interventional procedure to definitively close the PFO. It islikely, however, that a more prophylactic approach would be warranted toclose PFOs to prevent the prospective occurrence of a stroke. The costand potential side-effects and complications of such a procedure must below, however, since the event rate due to PFOs is relatively low. Inyounger patients, for example, PFOs sometimes close by themselves overtime without any adverse health effects.

Another highly prevalent and debilitating condition—chronic migraineheadache—has also been linked with PFO. Although the exact link has notyet been explained, PFO closure has been shown to eliminate orsignificantly reduce migraine headaches in many patients. Again,prophylactic PFO closure to treat chronic migraine headaches might bewarranted if a relatively non-invasive procedure were available.

Currently available interventional therapies for PFO are generallyfairly invasive and/or have potential drawbacks. One strategy is simplyto close a PFO during open heart surgery for another purpose, such asheart valve surgery. This can typically be achieved via a simpleprocedure such as placing a stitch or two across the PFO with vascularsuture. Performing open heart surgery purely to close an asymptomaticPFO or even a very small ASD, however, would be very hard to justify.

A number of interventional devices for closing PFOs percutaneously havealso been proposed and developed. Most of these devices are the same asor similar to ASD closure devices. They are typically “clamshell” or“double umbrella” shaped devices which deploy an area of biocompatiblemetal mesh or fabric (ePTFE or Dacron, for example) on each side of theatrial septum, held together with a central axial element, to cover thePFO. This umbrella then heals into the atrial septum, with the healingresponse forming a uniform layer of tissue or “pannus” over the device.Such devices have been developed, for example, by companies such asNitinol Medical Technologies, Inc. (Boston, Mass.) and AGA Medical, Inc.(White Bear Lake, Minn.). U.S. Pat. No. 6,401,720 describes a method andapparatus for thoracoscopic intracardiac procedures which may be usedfor treatment of PFO.

Although available devices may work well in some cases, they also face anumber of challenges. Relatively frequent causes of complicationsinclude, for example, improper deployment, device embolization into thecirculation and device breakage. In some instances, a deployed devicedoes not heal into the septal wall completely, leaving an exposed tissuewhich may itself be a nidus for thrombus formation. Furthermore,currently available devices are generally complex and expensive tomanufacture, making their use for prophylactic treatment of PFOimpractical. Additionally, currently available devices typically close aPFO by placing material on either side of the tunnel of the PFO,compressing and opening the tunnel acutely, until blood clots on thedevices and causes flow to stop.

Research into methods and compositions for tissue welding has beenunderway for many years. Such developments are described, for example,by Kennedy et al. in “High-Burst Strength Feedback-Controlled BipolarVessel Sealing,” Surg. Endosc. (1998) 12:876-878. Of particular interestare technologies developed by McNally et. al., (as shown in U.S. Pat.No. 6,391,049) and Fusion Medical (as shown in U.S. Pat. Nos. 5,156,613,5,669,934, 5,824,015 and 5,931,165). These technologies all discloseenergy delivery to tissue solders and patches to join tissue and formanastamoses between arteries, bowel, nerves, etc. Also of interest are anumber of patents by inventor Sinofsky, relating to laser suturing ofbiological materials (e.g., U.S. Pat. Nos. 5,725, 522, 5,569,239,5,540,677 and 5,071,417). None of these disclosures, however, showmethods or apparatus suitable for positioning the tissues of the PFO forwelding or for delivering the energy to a PFO to be welded.

Causing thermal trauma to a patent ovale has been described in twopatent applications by Stambaugh et al. (PCT Publication Nos. WO99/18870 and WO 99/18871). The devices and methods described, however,cause trauma to PFO tissues in hopes that scar tissue will eventuallyform and thus close the PFO. Using such devices and methods, the PFOactually remains patent immediately after the procedure and only closessometime later (if it closes at all). Therefore, a physician may notknow whether the treatment has worked until long after the treatmentprocedure has been performed. Frequently, scar tissue may fail to formor may form incompletely, resulting in a still patent PFO.

Therefore, it would be advantageous to have improved methods andapparatus for treating a PFO. Ideally, such methods and apparatus wouldhelp seal the PFO during, immediately after or soon after performing atreatment procedure. Also ideally, such devices and methods would leaveno foreign material (or very little material) in a patient's heart.Furthermore, such methods and apparatus would preferably be relativelysimple to manufacture and use, thus rendering prophylactic treatment ofPFO, such as for stroke prevention, a viable option. At least some ofthese objectives will be met by the present invention.

BRIEF SUMMARY OF THE INVENTION

The present invention generally provides methods, devices and systemsfor treating patent foramen ovale (PFO). As described in variousembodiments, by using a catheter device to bring tissues adjacent thepatent foramen ovale at least partially together and apply energy to thetissues, a PFO may be substantially closed acutely. By “substantially,”it is meant that a stable tissue bridge will be formed across the PFO,which will withstand physiologic pressures. A substantially closed PFO,however, may still have one or more small gaps or openings, which willin at least some cases close over time via the healing process. By“acutely,” it is meant that the PFO is substantially closed when theclosure procedure is completed. Thus, acute closure distinguishesembodiments described below from prior techniques, which rely on delayedPFO closure via tissue healing and scarring. “Acutely,” for purposes ofthis application, does not mean temporarily, since the variousembodiments will typically provide for permanent (or at least long-term)PFO closure.

The phrase “tissues adjacent a PFO,” or simply “PFO tissues,” for thepurposes of this application, means any tissues in, around or in thevicinity of a PFO which may be used or manipulated to help close thePFO. For example, tissues adjacent a PFO include septum primum tissue,septum secundum tissue, atrial septal tissue lateral to the septumprimum or septum secundum, tissue within the tunnel of the PFO, tissueon the right atrial surface or the left atrial surface of the atrialseptum and the like. By “application of energy,” it is meant that energymay be transferred either to or from PFO tissues. For example, ifcryogenic energy is applied, it could be said that heat energy istransferred out of the tissues. In various embodiments, any of a numberof energy transfer devices and forms of energy may be used to providesuch energy transfer. Types of energy used may include, for example,radiofrequency energy, cryogenic energy, laser energy, ultrasoundenergy, resistive heat energy, microwave energy and the like.

Application of energy to tissues to substantially close the PFO acutelymay sometimes be referred to as “tissue welding.” Preferably, tissuewelding methods of the present invention will be performed without usingtissue soldering material or other foreign material. In someembodiments, however, it may be advantageous to use one or more soldermaterials. Various solders and other tissue soldering matrices aredescribed more fully in U.S. patent application Ser. No. 10/665,974,which was previously incorporated by reference. Examples of tissuesolders or adhesives which may be used include, but are not limited to,autologous blood, albumin, collagen, fibrin, cyanoacrylates, musselbyssus adhesives, polymer hot melt adhesives and the like.

Embodiments described below provide for bringing tissues adjacent a PFOtogether (or “apposing” tissues). In various embodiments, tissues may beapposed before, during and/or after application or removal of energy tothe tissues. Generally, energy application or removal will act todenature collagen in the PFO tissues. If the tissues are apposed beforeand/or during denaturation and/or while the collagen in the tissues isallowed to renature, the collagen in once-separated tissues bindstogether to bring the tissues together. Therefore, some embodimentsinclude one or more devices for bringing (and possibly holding) tissuestogether before, during and/or after energy application or removal. Byproviding for substantial, acute closure of a PFO, devices, systems andmethods may be advantageous for preventing stroke, treating migraineheadaches and/or preventing or treating other medical conditions causedor exacerbated by PFO.

In one aspect of the present invention, a method of treating a PFO in aheart involves advancing a catheter device to a position in the heartfor treating the PFO, bringing tissues adjacent the PFO at leastpartially together using the catheter device, and applying energy to thetissues with the catheter device to substantially close the PFO acutely.In some embodiments the tissues are brought together before applying theenergy. Optionally, the tissues may then be held together while applyingthe energy. In some embodiments, the tissues may be held together afterthe energy has been applied as well, to allow the tissues to cool,renature, close the PFO and/or the like. Optionally, the method mayfurther involve actively cooling the tissues after the energy has beenapplied.

In some embodiments, after applying energy to the tissues, the catheterdevice may be moved to a different position relative to the PFO, tissuemay be brought together again, and energy may be applied again. Someembodiments involve multiple repetitions of the moving, bringingtogether and energy application steps. In such embodiments, the PFO maybe substantially closed by moving along the PFO with the catheterdevice, typically from one side of the PFO to another, and bringingtogether tissues and applying energy multiple times. Such a method maybe referred to as “spot welding” of PFO tissues. In some embodiments,one or more biasing members on the catheter may be used to bias thecatheter toward one side of the PFO. For example, the shape of acatheter body, an expandable member, a biasing wire or the like may helpurge the catheter to one side. Typically, the catheter may then be movedacross the PFO, bringing tissues together and applying energy atmultiple positions along the way. In one embodiment, for example, tissueapposition members (which may also be configured to apply energy to thetissues) squeeze tissue between them. As they do so, they may alsosqueeze a shaped catheter body between the tissues, and thecross-sectional shape of the catheter body may cause it to be urged to anew position as the tissue is squeezed down upon it. For example, thecatheter body may have a triangular, oval, diamond, or other shape.After energy is applied at the first position, the tissue appositionmembers are moved to the second position and again squeeze down ontissue and the catheter body, thus urging the catheter body to a thirdposition and so on.

A number of other suitable techniques are also contemplated for movingacross the PFO and “spot welding” the tissues. In another embodiment,for example, a large stationary electrode is positioned either in theright or left atrium and a smaller mobile electrode is moved along thePFO in the other atrium to create spot welds. In other embodiments, oneor more electrodes may be rotated around the circumference of the PFO.

Advancing the catheter device to a position in the heart for treatingthe PFO may be accomplished by any suitable technique. In someembodiments, for example, a first distal portion of the catheter isadvanced to a location in the right atrium and that first distal portionis used for bringing tissues together. In some embodiments, a seconddistal portion may be advanced into or through the PFO, and the firstand second distal portions are then used to appose the tissues. In someembodiments, the second portion extends through the PFO and into theleft atrium, so that the first portion contacts tissue from the rightatrial side and the second portion contacts tissue from the left atrialside. In various embodiments, either one or both of the portions maythen be manipulated to bring the tissues together between them. Forexample, one or both portions may be moved axially toward one another.In some embodiments, one portion is moved axially toward the otherportion, the latter portion being held relatively stationary to act as a“backstop” or surface against which to bring the tissues together. Manysuch backstop devices are described in patent application Ser. Nos.60/458,854, 60/478,035, and 60/490,082, which were all incorporated byreference above. Optionally, either or both of the portions may also beused to apply energy to the tissues.

Bringing the tissues at least partially together may be accomplished byany of a number of suitable methods. For example, as just mentioned,first and/or second distal portions of the catheter device may be movedtoward one another to trap, clamp, grasp, grip or otherwise apposetissues between the two members. In another embodiment, tissues may bebrought together by expanding one or more expandable members. Forexample, one expandable member may be expanded in either the right orleft atrium to push against tissue and thus bring them together. Inanother embodiment, one expandable member may be expanded in the rightatrium and a second expanded in the left atrium, with the expansioncausing the tissues to be squeezed together between the two members. Asimilar result may be achieved by using one expandable member and a“backstop” member, as described above. Some embodiments further includemoving one expandable member toward the other to further bring thetissues together. For example, an expandable member may be slid axiallytoward another expandable member along the catheter device. Again, anysuitable technique may be used.

In alternative embodiments, bringing the tissues together may involvedeploying an expanding member within the PFO. The expanding member, suchas two-pronged “fish-mouthing ” member, is typically disposed in asheath while advanced into the PFO. The sheath is then retracted toallow the prongs to expand away from each other. Such expanding,“fishmouth,” two-pronged members may be constructed of shape memorymaterials, spring-loaded materials or the like. By spreading PFO tissueslaterally between two prongs, the tissues come together in the areabetween the prongs. In some embodiments, one or more expandable membersmay be coupled with the prong(s) or the catheter device to furtherassist in bringing the tissues together. Optionally, the method may alsoinclude contacting a left atrial surface of at least one of a septumprimum and a septum secundum with a distal portion of the expandingmember and retracting the expanding member to bring the tissues adjacentthe PFO together. For example, the distal portion may contact the septumprimum and pull it toward the right side of the heart, into contact withthe septum secundum. At some point after the expanding member has beenused to appose the tissues adjacent the PFO, it may be advantageous toretract the expanding member to a position within the catheter device.For example, the expanding member may be retracted in some embodimentsbefore removing the catheter device.

In other embodiments, the first distal portion and/or the second distalportion of the catheter device may be advanced into tissues adjacent thePFO. In other words, one or more portions of the catheter device may becaused to pierce into PFO adjacent tissues. Such an embodiment, forexample, may involve use of a jaw-like device, with the first and secondtissue apposition members comprising opposing jaws. In one embodiment,for example, the first distal portion is advanced into septum secundumtissue. Optionally, the second distal portion may be advanced intoseptum primum tissue. The first and second tissue apposition members maythen be moved together to bring tissues together. In yet anotherembodiment, a clamp-like device may be used, either with or withoutpiercing tissues. With clamping, one portion of the clamp may contacttissue from the right atrium, and the other may contact tissue from theleft atrium. Again, any of a number of other suitable techniques may beused, some of which are described more fully in U.S. patent applicationSer. Nos. 60/458,854, 60/478,035, 60/490,082, 10/665,974, and10/679,245, which were all previously incorporated by reference.

In some embodiments the catheter device may be advanced over aguidewire. The guidewire typically extends through the PFO and mayinclude an expanding portion along its length for expanding within thePFO. Optionally, the guidewire may extend into the left atrium, and themethod may optionally include contacting a left atrial surface of atleast one of a septum primum and a septum secundum with a distal portionof the guidewire and retracting the guidewire to bring the tissuesadjacent the PFO together.

Any suitable type of energy may be applied to the PFO tissues to provideacute PFO closure. In some embodiments, for example, monopolar orbipolar radiofrequency energy is applied, while in alternativeembodiments cryogenic, resistive heat, ultrasound, microwave, or laserenergy, heat energy in the form of heated fluid such as saline, or thelike may be applied. Energy may be applied by energizing a singleconductive member of the catheter device or multiple conductive members,in various embodiments. Generally, any suitable devices for energydelivery are contemplated. In one embodiment, applying energy to thetissues involves applying energy to a conductive fluid and releasing theconductive fluid from the catheter device to contact the tissues. Forexample, a conductive fluid such as saline may be introduced into one ormore expandable members of the catheter device, energy such as radiofrequency energy may be applied to the fluid, and the fluid may then bereleased from the expandable member(s) through at least one, andpreferably many, small apertures on the expandable member. The energizedconductive fluid then contacts the tissues to close the PFO.

Some embodiments of the method may further involve monitoring an amountof energy applied to the tissues. For example, monitoring the energy mayinvolve monitoring a temperature of the tissues, an impedance of thetissues and/or the like. Such a method may further involve determiningwhen a sufficient amount of energy has been applied to the tissues toacutely close the PFO. Optionally, the method may also includediscontinuing the application of energy when the sufficient amount ofenergy has been applied.

Any of the above methods may also involve directly visualizing the PFOand the adjacent tissues using at least one visualization device coupledwith the catheter device. Such a visualization device may include afiber optic device, an ultrasound device or any other suitablevisualization device.

In another aspect of the present invention, a method of treating apatent foramen ovale in a heart includes: advancing a catheter device toa position in the heart for treating the patent foramen ovale; bringingtissues adjacent the patent foramen ovale at least partially togetherusing the catheter device; applying energy to the tissues with thecatheter device while holding the tissues at least partially together;and holding the tissues at least partially together for a sufficienttime after applying the energy to substantially close the patent foramenovale. Such a method may include any of the features of the embodimentsdescribed above.

In yet another aspect of the invention, a catheter device for treating apatent foramen ovale in a heart includes an elongate catheter bodyhaving a proximal end and a distal end, at least one tissue appositionmember at or near the catheter body distal end for bringing tissuesadjacent the patent foramen ovale at least partially together, and atleast one energy transmission member at or near the distal end forapplying energy to the tissues to substantially close the patent foramenovale acutely. In some embodiments, the at least one tissue appositionmember comprises a first tissue apposition member for contacting tissuefrom the right atrium of the heart. Optionally, a second tissueapposition member may be included for contacting tissue either from theright atrium or the left atrium, in various embodiments. For example, inone embodiment the first and second members may comprise a set ofopposable jaws that may be used from within the right atrium to bringthe tissues together, optionally advancing through one or of thePFO-adjacent tissues. In other embodiments, the second member may beadvanced through the PFO to contact the tissue from the left atrium. Anynumber of different tissue apposition members may be included.

As described above, for example, one or both of first and second tissueapposition members may comprise expandable members, and either (or both)may be axially slidable toward the other to bring tissue togetherbetween them. In other embodiments, one expandable member and one shapeddeployable “backstop” member may be used. The deployable member, forexample, may comprise a shape-memory device which is advanced into theleft atrium and deployed to contact tissue. An expandable balloon may beexpanded and possibly moved axially along the catheter to bring thetissue together between it and the deployable backstop. Any one or moreof such expandable members may also include at least one small aperturefor allowing conductive fluid to escape from expandable member tocontact the tissues. Some embodiments include multiple small apertures,and some include two expandable members with apertures.

In other embodiments, first and second tissue apposition members areconfigured as arms of a clamp, with one arm disposed in the right atriumand the other in the left atrium, for clamping tissues together. Stillother embodiments may include one set of opposable jaws and one hook orclamp member to bring the tissue toward the clamp. In other embodiments,the first and second members are configured as a clip, “bobby pin,” orthe like, wherein the relative shapes of the first and second appositionmembers urge the tissues together. For example, in one embodiment one ofthe members may be shaped as a hook or similarly curved member forhooking over the PFO to contact the tissues from the left atrium, whilethe other member may be relatively straight to contact the tissues fromthe right atrium. Tissues may thus be grasped together between the twomembers, bringing them together, not unlike an object placed between thetongs of a bobby pin or within the curves of a paper clip.

Some embodiments of the apparatus further include a guide member foradvancing through the PFO, with the catheter device being slidablydisposed over the guide member. The guide member may include, forexample a guide catheter and at least one expandable member disposedwithin the guide catheter, wherein the guide catheter is retractable toexpose the expandable member to allow it to expand within the PFO. Theexpandable member, in turn, may have any suitable configuration, but insome embodiments it includes at least two members that expand apart toprovide lateral force to the tissues adjacent the PFO, such as a“fishmouth” or two-prong expandable member. When exposed, the expandingmember may also provide dilatory force to the tissues adjacent the PFO.To provide expandability, the expandable member may be made of shapememory material, may be spring loaded, and/or the like.

In alternative embodiments, the guide member may comprise a guidewirehaving an expandable portion along its length. For example, theexpandable portion may be a divided portion, the divided portioncomprising expandable shape memory material. Optionally, the guidemember may include at least one tip for contacting a left atrial surfaceof the tissues adjacent the PFO. Such a tip may be conformable to theleft atrial surface. The guide member may be retractable to engage theat least one tip with the left atrial surface. In any of the aboveembodiments, one or more guide members, or component parts of a guidemember, may act as one or more energy transmission members. In someembodiments, for example, an expanding member may act as a monopolar orbipolar radiofrequency electrode.

The at least one energy transmission member of the catheter device maycomprise any suitable energy transmission device or combination ofdevices. For example, the transmission member may transmitradiofrequency energy, cryogenic energy, resistive heat energy,ultrasound energy, microwave energy, laser energy or any other form ofenergy for treating PFO tissues. In preferred embodiments, the energytransmission member comprises a monopolar or two bipolar radiofrequencytransmission members. Such a transmission member, for example, may becurved to approximate the curvature of the PFO. In other embodiments,straight transmission members, mesh or braided transmission members,multiple pin-point transmission members or the like may be used.

In some embodiments, one or more energy transmission members are coupledwith one or more tissue apposition members. In some embodiments, forexample, one or more energy transmission members simply act as tissueapposition members. In some embodiments, energy transmission member ismovable along at least part of a circumference of the at least onetissue apposition member. In alternative embodiments, the energytransmission member comprises a guide member for advancing through thePFO, with the catheter device being slidably disposed over the guidemember. Again, the guide member typically includes at least oneexpandable portion for expanding within the PFO to at least partiallybring together the tissues adjacent the PFO, and in some embodiments theexpandable member acts as the energy transmission member(s). In stillother embodiments, energy transmission members may be coupled with boththe tissue apposition member and the guide member/expandable member.

As described above, in one embodiment the at least one energytransmission member include one or more energy transmission memberdisposed within an expandable member for applying energy to a conductivefluid. The energy transmission member further includes one or moreconductive fluids which are introduced into the expandable member(s) andthen allowed to escape from the expandable members, typically viamultiple apertures. In various embodiments, one, two or more expandablemembers with apertures, conductive fluid and an energy transmissionmember may be included. In one embodiment, radio frequency energy istransmitted to saline solution as the conductive fluid, but inalternative embodiments other forms of energy and/or conductive fluid(s)may be used.

Some embodiments of the catheter device may further include at least onesensor coupled with the catheter device for sensing an amount of energydelivered to the tissues by the at least one energy transmission member.Sensors, for example, may be infrared sensors, thermistors,thermocouples or the like, though any sensors may be used. Optionally, amicroprocessor may be coupled with the at least one sensor forprocessing sensed data to determine when the amount of delivered energyhas reached a desired amount of energy.

In another aspect of the invention, a system for treating a patentforamen ovale in a heart includes a catheter device and at least oneguide member for guiding the catheter device to a position for treatingthe patent foramen ovale. The catheter device includes an elongatecatheter body having a proximal end and a distal end, at least onetissue apposition member at or near the catheter body distal end forbringing tissues adjacent the patent foramen ovale at least partiallytogether, and at least one energy transmission member at or near thedistal end for applying energy to the tissues to substantially close thepatent foramen ovale. The catheter device may include any of thefeatures or variations described above.

These and other embodiments are described in further detail in thefollowing description related to the appended drawing figures.

BRIEF DESCRIPTION OF THE DRAWING FIGURES

FIG. 1 is a diagram of the fetal circulation;

FIG. 2 is a diagram of a catheter apparatus according to an embodimentof the present invention, the catheter passing through the inferior venacava and right atrium and through the PFO;

FIG. 3 is a perspective view of a distal portion of a catheter apparatushaving two expandable members according to an embodiment of the presentinvention;

FIG. 4 is a perspective view of a distal portion of a catheter apparatushaving two expandable members according to another embodiment of thepresent invention;

FIG. 5 is a perspective view of a distal portion of a catheter apparatushaving one expandable member according to another embodiment of thepresent invention;

FIG. 6 is a perspective view of a distal portion of a catheter apparatushaving one expandable member and a shape-memory member according toanother embodiment of the present invention;

FIG. 7 is a perspective view of a distal portion of a catheter apparatushaving two expandable members coupled with two prongs according toanother embodiment of the present invention;

FIG. 8 is a perspective view of a distal portion of a catheter apparatushaving one expandable member and two prongs according to anotherembodiment of the present invention;

FIG. 9 is a cross-sectional view of a distal portion of a catheterapparatus having two tissue apposition members and a shaped catheterbody according to another embodiment of the present invention;

FIG. 10 is a perspective view of a distal portion of a catheterapparatus having two tissue apposition members and a shaped catheterbody according to another embodiment of the present invention;

FIGS. 11A-11C are perspective views of a distal portion of a catheterapparatus, demonstrating a method for bringing tissues togetheraccording to another embodiment of the present invention;

FIGS. 12A and 12B are perspective views of a distal portion of acatheter apparatus having opposable jaws according to another embodimentof the present invention;

FIGS. 13A and 13B are perspective views of a distal portion of acatheter apparatus having opposable jaws according to another embodimentof the present invention;

FIG. 14 is a perspective view of a distal portion of a catheterapparatus having a two-prong tissue apposition member with vacuumaccording to another embodiment of the present invention;

FIGS. 15A and 15B are perspective views of a distal portion of acatheter apparatus having opposable jaws and a curved member accordingto another embodiment of the present invention;

FIGS. 16A and 16B are perspective views of a distal portion of acatheter apparatus having magnetic tissue apposition members accordingto another embodiment of the present invention;

FIG. 17 is a perspective view of a distal portion of a catheterapparatus having clamping tissue apposition members according to anotherembodiment of the present invention;

FIG. 18 is a right atrial view of a PFO with a stationary energytransmission member in the right atrium and multiple tissue weldsaccording to another embodiment of the present invention;

FIG. 19 is a perspective view of a distal portion of a catheterapparatus having two expandable members and a guidewire extendingthrough the right and left atria of the heart according to anotherembodiment of the present invention;

FIGS. 20A-20C are perspective views of a distal portion of a catheterapparatus having two separate tissue apposition members according toanother embodiment of the present invention;

FIGS. 21A-21B demonstrate treating a PFO using a closure device having abackstop according to an embodiment of the present invention;

FIGS. 22A-22D demonstrate treating a PFO using a spring coil closuredevice according to an embodiment of the present invention;

FIG. 23 demonstrates treating a PFO using a spring coil closure deviceaccording to another embodiment of the present invention; and

FIG. 24 demonstrates treating a PFO using a spring coil closure deviceaccording to another embodiment of the present invention.

DETAILED DESCRIPTION OF THE INVENTION

Devices and methods of the present invention generally provide forpatent foramen ovale (PFO) treatment through application of energy.Methods involve advancing a catheter device to a position in the heartfor treating the PFO, bringing tissues at least partially together usingthe catheter, and applying energy to tissues adjacent a PFO tosubstantially close the PFO acutely. Devices of the invention generallyinclude a catheter device having a proximal end and a distal end, atleast one tissue apposition member, and at least one energy transmissionmember adjacent the distal end.

FIG. 1 is a diagram of the fetal circulation. The foramen ovale isshown, with an arrow demonstrating that blood passes from the rightatrium to the left atrium in the fetus. After birth, if the foramenovale fails to close (thus becoming a PFO), blood may travel from theright atrium to the left atrium or vice versa, causing increased risk ofstroke, migraine and possibly other adverse health conditions, asdiscussed above.

With reference to FIG. 2, one embodiment of a catheter device 10 fortreating PFO suitably includes a catheter body 12 and one or more tissueapposition members 14. Catheter device 10 may be advanced through thevasculature of a patient to a position in the heart for treating a PFO.For example, as shown catheter device 10 has been advanced through theinferior vena cava into the right atrium of the heart. In alternativeembodiments, a catheter device may be advanced through the aorta to theleft ventricle and then into the left atrium of the heart to treat thePFO. In some embodiments, two separate portions of a catheter apparatusmay be advanced to the right atrium and left atrium, and in yet anotherembodiment, a guidewire or other component of a catheter apparatus mayextend from outside the patient, through the vasculature to the rightatrium, through the PFO to the left atrium, and out the aorta to thevasculature to exit the patient from a second site. Various embodimentsmay thus make use of any suitable access technique for disposing acatheter device in a location for treating a PFO.

Catheter body 12 typically comprises an elongate, flexible body havingat least one lumen. Catheter body 12 may be manufactured from anysuitable material or combination of materials known in the catheter artsor hereafter discovered, such as PTFE, other polymers or the like.Catheter body 12 may also having any suitable size, profile, diameter,shape and the like. Optionally, catheter body 12 may be slidablydisposed over a guide member (not shown), such as a guide catheter,guidewire, or the like. In some embodiments, such a guide member mayinclude one or more expanding members or other similar devices fordeploying within the PFO to help appose the adjacent tissues. Forfurther description of such expandable guide members, reference may bemade to U.S. patent application Ser. No. 10/679,245, which waspreviously incorporated by reference.

Tissue apposition members 14 generally may include any one, two or moredevices for helping bring tissues adjacent the PFO together. As shown inFIG. 2, one member 14 may be disposed in the right atrium to contacttissue from the right atrial side, such as septum secundum tissue, whilethe other member 14 may be advanced through the PFO to contact tissuefrom the left atrium. In some embodiments, tissue apposition members 14may be pre-shaped and manufactured from shape-memory material, springstainless steel or the like, such that when they are released fromcatheter body 12, they take on a shape that allows them to bring thetissues together.

Catheter device 10 also includes at least one energy transmissionmember. In the embodiment shown, either one or both of tissue appositionmembers 14 may also act as energy transmission members. In variousembodiments, energy transmission members may be capable of bringing thetissues together, energy transmission members may be coupled with tissueapposition members, or energy transmission members may be separate fromand not coupled with tissue apposition members. Also in variousembodiments, one energy transmission member may be used, such as toprovide monopolar radiofrequency energy (RF), two transmission membersmay be used, such as to provide bipolar RF energy, or more than twotransmission members may be used.

Referring now to FIG. 3, another embodiment of a catheter device 20 forPFO treatment suitably includes a catheter body 22, a first expandablemember 27 having a first energy transmission member 23, and a secondexpandable member 28 having a second energy transmission member 25, witheach expandable member 27, 28 including multiple apertures 24 forallowing passage of conductive fluid 26. Expandable members 27, 28 maybe positioned for treatment, such as in the right atrium (first member27) and the left atrium (second member 28) and then expanded to bringtogether tissues of the septum secundum SS, septum primum SP and/orother PFO-adjacent tissue. In some embodiments, one or both ofexpandable members 27, 28 may also be moved axially along catheter body22, such as by sliding, so as to bring the tissues together between thetwo expandable members 27, 28. For example, second expandable member 28may be disposed on a separate catheter body disposed over or withincatheter body 22 to allow second member 28 to axially slide back andforth along catheter body 22.

Expandable members 27, 28 may comprise any suitable material orcombination of materials now known or developed in the future.Expandable balloon members for use on catheters are well known, and anysuitable variation may be used in various embodiments of the invention.Expandable members 27, 28 may be made of conformable elastomericmaterials, polymers or the like and may have any suitable shape uponexpansion.

Energy may be applied to the tissues by introducing one or moreconductive fluids 26, such as saline solution or the like, intoexpandable member 27, 28, applying energy (such as RF energy) toconductive fluids 26 via energy transmission members 25, 27, and thenallowing fluid(s) 26 to pass from apertures 24 to contact the tissues.Thus, the fluid 26 may provide the needed energy to the tissues to causeclosure of the PFO. After transmitting the energy to the nearby PFOtissues, conductive fluid 26 harmlessly dissipates in the body.

In various embodiments, energy transmission members may comprise any ofa number of devices and may transmit any suitable type of energy forclosing a PFO. Some types of energy which may be used, for example,include radiofrequency, cryogenic, resistive heat, ultrasound, microwaveand laser energy. Radiofrequency energy transmission members may beeither monopolar or bipolar, with monopolar catheter devices alsoincluding a grounding member. Energy transmission members may also haveany suitable configuration, many of which are described below inreference to specific embodiments. In some embodiments, energytransmission members are fixedly coupled with tissue apposition member,while in other embodiments energy transmission members are movablewithin tissue apposition member, for example to move about thecircumference of the PFO to weld PFO tissues at multiple locations. Insome embodiments, energy delivery is achieved by circulating cooled orheated fluids within expandable members 27, 28, without allowing suchfluids to pass out of expandable members 27 & 28. In these embodiments,apertures 24 are eliminated from the design.

Energy transmission members 23, 25 provide sufficient energy transfer,for a sufficient time, to weld the tissues. The time span of energytransmission may be, for example, from about 0.5 seconds to about 15minutes, and more preferably from about 30 seconds to about 5 minutes.Energy transmission, in some embodiments, may be from about 0.5 Watts toabout 100 Watts, and more preferably from about 5 Watts to about 50Watts. In various embodiments, any other suitable energy and timingcombination may alternatively be used. In one experimental example, aPFO in a section of pig heart tissue used ex-vivo in a flowing salinetest fixture was closed by applying suction to appose the PFO tissuesand applying RF energy at approximately 25 Watts for 7 minutes. RFenergy application was then discontinued, but tissue apposition wascontinued for an additional 1 minute to hold tissues together whilecooling, thus allowing collagen in the tissues to reorganize and bindtogether to form a stable tissue bridge. In alternative embodiments,other energy amounts, energy application times, tissue apposition timesand the like may be used.

Although any suitable type of energy may be transmitted by energytransmission members in various embodiments, some embodiments make useof monopolar or bipolar radiofrequency (RF) energy. Devices may usemonopolar radiofrequency energy, for example, wherein energy is appliedsimultaneously to all conductive elements, completing the circuitthrough an external ground pad affixed to the skin of the patient.Alternatively, bipolar energy may be applied to all conductive elementssimultaneously, and the circuit completed through a ground elementincorporated elsewhere on the catheter device. Further embodiments mayinclude applying bipolar energy between two or more energy transmissionmembers, which are electrically isolated from one another withincatheter device.

Control systems coupled with energy transmission members or tissueapposition members, or otherwise disposed within a catheter device, maysense an amount of energy delivered to PFO tissues and, optionally, mayautomatically stop energy delivery upon detecting a change in conditionof energy delivery, for instance an increase in electrical resistance orimpedance in PFO tissues or in the catheter device, an increased energydraw from the catheter device, and/or the like. In some embodiments,energy delivery may be automatically stopped when an amount of deliveredenergy reaches a desired level, such as an amount of energy sufficientto substantially close the PFO. The amount of delivered energy may bemonitored by any suitable method, such as monitoring temperature orimpedance in PFO tissues or the like. In some embodiments, one or moresensors coupled with tissue apposition members, energy transmissionmembers, or any other part of a catheter device may be used formonitoring such indicia. Examples of sensor devices include but are notlimited to infrared sensing devices, thermistors and thermocouples.Optionally, a control system may also include a microprocessor coupledwith the sensors to determine when a desired amount of energy has beendelivered and/or to automatically stop energy transmission. Inalternative embodiments, a microprocessor may be attached to a catheterdevice which can sense, monitor and control energy delivery, thus notrequiring separate sensors.

FIG. 4 shows a slightly different embodiment of a catheter device 30having a catheter body 32, a first expandable member 37 and a secondexpandable member 38 having an energy transmission member 35 andmultiple apertures 34 for allowing passage of a conductive fluid 36. Inthis embodiment, first expandable member 37 may be used as a tissueapposition member without providing additional energy transmission.

Referring to FIG. 5, an alternative embodiment of a catheter device 40for treating PFO includes a catheter body 42, an expandable member 48having apertures for allowing passage of fluid 46, and an energytransmission member 45. In this embodiment, expanding expandable member48 may be sufficient to bring tissues together, or proximally directedforce may be applied to expandable member 48, such as by pulling back oncatheter body 42, to bring the tissues together.

Referring now to FIG. 6, one embodiment of a catheter device 50 includesa catheter body 52, an expandable member 57 having an energytransmission member 53 disposed within it and apertures 54 on itssurface for allowing passage of conductive fluid 56, and a shaped distalportion 59. Shaped distal portion 59 resides in the left atrium and actsas a surface or “backstop,” such that tissue may be brought togetherbetween shaped distal portion 59 and expandable member 57. In theembodiment shown, shaped portion 59 is a helical coil, which may be madeof shape memory material, spring stainless steel or the like, so that ithas a relatively straight configuration while disposed within catheterbody 52, but assumes the coiled configuration when released. In otherembodiments, other backstop devices may be used, such as those describedmore fully in U.S. patent application Ser. No. 60/478,035, which waspreviously incorporated by reference.

FIG. 7 shows another embodiment of a catheter device 60, which includesa catheter body 62, a two-pronged tissue apposition member 64, and twoexpandable members 66 coupled to the two prongs 64 for providing furthertissue apposition. Tissue apposition member 64, the prongs of which maycomprise nitinol, some other shape memory material, or the like, istypically released from catheter body 62 within a PFO to allow theprongs 64 to expand apart. The tissue between the prongs is thus broughttogether, in essence flattening or “fish-mouthing.” For further tissueapposition expandable members 66 may be expanded, and optionally,proximal force may be applied, such as by pulling back on catheter body62, to urge the tissues together with expandable members 66. Prongs 64then act as energy transmission members for applying energy to thetissues. Typically, prongs 64 are bipolar RF energy transmissionmembers, but alternative embodiments are also contemplated.

In an alternative embodiment, and referring now to FIG. 8, a catheterdevice 70 may include a catheter body 72, a two-pronged tissueapposition member 74, and a separate expandable member 76 for enhancingtissue apposition. Again, tissue apposition members 74 may also act asenergy transmission members. Additionally or alternatively, aperturesmay be provided in expandable member 76 for introducing conductive fluidas a portion of the energy delivery system.

With reference now to FIG. 9, in another embodiment a catheter device 80suitable includes a catheter body 86, a first tissue apposition member82 and a second tissue apposition member 84. As mentioned previously,one or both of tissue apposition members 82, 84 may be coupled with ormay act as energy transmission members. In this embodiment, first tissueapposition member 82 is configured to contact tissue from the rightatrium, such as septum secundum tissue SS, while second appositionmember 84 is configured to contact tissue from the left atrium, such asseptum primum tissue SP. In contacting and bringing these tissuestogether (hollow-tipped arrows), tissue apposition members 82, 84 alsobring the tissues together (or squeeze the tissues) against catheterbody 86. When force is applied against catheter body 86, it is urged toone side (solid-tipped arrows), due to its cross-sectional shape. In theembodiment shown, catheter body 86 has a triangular cross-section,though in alternative embodiments it may have other shapes, such asoval, ellipsoid, diamond-shaped, or the like. When catheter body 86 isurged aside, tissue apposition/energy transmission members 82, 84 areused to apply energy to tissue in a first location. Apposition members82, 84 may then be moved to the side, toward catheter body 86, to bringadjacent tissues together, thus urging catheter body 86 further alongthe PFO. Energy may then be applied again to the tissue in the secondlocation. Using such a technique, it may be possible to move catheterdevice 80 across a PFO from one side to another, applying energy andclosing the PFO as device 80 is moved. In other words, catheter devices“walks” along the PFO, spot tissue welding as it goes.

FIG. 10 shows one embodiment of a catheter device 90 which may be usedin a method similar to the one just described. Device 90 includes acatheter body 92, a first tissue apposition member 94, and a secondtissue apposition member 96, and is shown disposed over a guidewire 98.In this embodiment, tissue apposition members 94, 96 also act as energytransmission members. First tissue apposition member 94 is aspring-loaded jaw, and second tissue apposition member 96 is ashape-memory energy transmission member, such as an electrode. Asdescribed above, when tissue apposition members 94, 96 bring tissueadjacent the PFO together, they bring the tissue together againstcatheter body 92, thus squeezing catheter body 92 aside. After applyingenergy to the tissues, tissue apposition members 94, 96 may then bemoved toward catheter body 92 again and used to bring tissue togetheragain, thus squeezing catheter body 92 aside again. To enhance such atechnique, catheter body 92 may include one or more slick or slipperysurfaces, to allow it to more easily slide to the side. Catheter body 92may also include a coating of a tissue welding substance, solder or thelike, such as albumin, which partially rubs off each time catheter bodyis squeezed aside, thus enhancing application of energy to the tissuesto close the PFO. Catheter body 92 may further include one or moreapertures for introducing a fluid at the location of energy application,to act as a welding fluid or to otherwise enhance tissue welding.

In the embodiments described in FIGS. 9 and 10, as well as in otherembodiments, a catheter device may also include a biasing member forbiasing the catheter device toward one side of a PFO to start a PFOclosure procedure. For example, an expandable member may be coupled witha catheter body, typically on one side of the body, such that when thecatheter device is positioned in the PFO and the expandable member isexpanded, the catheter device is urged to one side of the PFO. Tissuemay then be brought together and welded at that side and the expandablemember may be gradually deflated to allow the catheter device to movetoward the other side of the PFO, bringing tissue together and applyingenergy as it goes. A similar result may be achieved with a biasing wire,a catheter body having a biasing shape, or the like.

Referring now to FIGS. 11-11C, in another embodiment a catheter device100 for treating a PFO includes a catheter body 106, a first tissueapposition member 104 and a second tissue apposition member 102. Tissueapposition members 102, 104 comprise shape memory material energytransmission members made of nitinol or any other suitable shape memorymaterial(s). To deploy tissue apposition members 102, 104, catheter body106 is first advanced through the PFO, as shown in FIG. 11A. Catheterbody 106 is then withdraw/retracted and second tissue apposition member102 is advanced (solid-tipped arrows), so that second tissue appositionmember 102 is released from the distal end of catheter body 106. Asshown in FIG. 11B, catheter body 106 may then be advanced again to pushagainst a surface of second tissue apposition member 102, thus openingapposition member (solid-tipped arrows) to fit over PFO-adjacent tissuesuch as the septum primum. This technique is analogous to expanding thetines of a bobby pin. As shown in FIG. 11C, after second tissueapposition member 102 is placed in contact with the septum primum,catheter body 106 may be retracted again and first tissue appositionmember 104 may be advanced to expose first member 104. Tissues are thembrought together between the two apposition members 102, 104 and themembers 102, 104 are used to apply energy to the tissues to close thePFO.

FIGS. 12A and 12B show another embodiment of a catheter device 110 fortreating PFO, including a catheter body and a pair of opposable jaws114. Jaws 114 may be used to grasp tissue adjacent the PFO, such asseptum secundum SS and septum primum SP tissues, to bring them togetherfor energy application and tissue welding. Jaws 114 may also comprisesenergy transmission members, such as two electrodes of a bipolar RFdevice, one electrode and one energy return member of a monopolar RFdevice, or the like. In some embodiments, one or both jaws 114 may beadvanced through (or in other words pierce into) PFO tissues. Here, asdesignated by the dotted lines, one jaw is advanced into septum primumSP tissue. FIG. 12A shows jaws 114 expanded, and FIG. 11B shows jaws 114drawn together to draw the tissues together.

Referring to FIGS. 13A and 13B, catheter device 110 is shown with bothjaws 114 piercing tissue adjacent the PFO. Again, jaws 114 are expandedin FIG. 13A and drawn together in 13B to bring the tissues intoapposition.

Referring now to FIG. 14, in one embodiment a catheter device 120 fortreating PFO suitably include a catheter body 122 and a two-pronged,“fish mouth” tissue apposition member 124 having multiple vacuumapertures 126 for applying a vacuum force to enhance tissue apposition.As already described, tissue apposition prongs 124 may be deployedinside the PFO to bring tissues together, and vacuum apertures 126 maythen be used to further appose the tissues. Energy may then be appliedvia tissue apposition prongs 124, which may comprise bipolar RF energytransmission members in one embodiment.

With reference to FIGS. 15A and 15B, another embodiment of a catheterdevice 130 suitably includes a catheter body 132, a grasping tissueapposition member 134, and a shape memory tissue apposition member 136.These tissue apposition members 134, 136 may be used to contact tissuefrom right and left atrial sides of the PFO, as in FIG. 15A, and thenused to bring the tissues together, as in FIG. 15B. Either or bothtissue apposition members 134, 136 may also act as energy transmissionmembers.

In FIGS. 16A and 16B, a catheter device 140 includes a catheter body142, a positively charged magnet 144 and a negatively charged magnet146. The magnets 144, 146 act as both tissue apposition members andenergy transmission member and bring tissue together between them due totheir opposite polarities, as shown in FIG. 16B.

In another embodiment, as shown in FIG. 17 in a perspective from insidethe right atrium, a tissue apposition member 150 of a catheter devicefor treating PFO may comprise a clamp, including a first clamp arm 152for positioning in the right atrium and a second clamp arm 154 forpositioning in the left atrium. The arms 152, 154 are then broughttogether to bring the tissues together.

In FIG. 18, again from a perspective from inside the right atrium, onlyan electrode 162 is shown. In one embodiment of the device, a relativelylarge electrode 162 may be positioned in the right atrium and maintainedin approximately the same position throughout a procedure. A smallerelectrode may then be disposed in the left atrium and moved along thetissues of the PFO to create spot tissue welds 164 to close the PFO.Pressure and bipolar RF energy is directed between the smaller electrodeand the larger electrode 162, to bring the tissue together and applyenergy to close the PFO.

Referring now to FIG. 19, in yet another embodiment, a catheter system170 for treating PFO may include a first catheter body 172 having afirst expandable member 176, a second catheter body 174 having a secondexpandable member 178 and a guidewire 179. In one embodiment, guidewireextends from an entry point on the patient, such as a femoral vein,through the inferior vena cava IVC, right atrium RA, PFO and left atriumLA, and then through the left ventricle, aorta, and eventually out afemoral artery. Catheter bodies 172, 174 may be advanced to locations inthe right and left atria respectively along this guidewire. In analternative embodiment, two guidewires may be used, and they may becoupled within the PFO or elsewhere within the heart.

In another embodiment, as shown in FIGS. 20A-20C, a catheter device 180includes a catheter body 182, a left atrial tissue apposition member 184and a separate right atrial tissue apposition member 186. FIG. 20A showsjust catheter body 182 and left atrial member 184 from a right atrialview, with left atrial member 184 hooking over the PFO into the leftatrium. FIG. 20B is a close-up view from the perspective of the distalend of left atrial member 184 hooking into the left atrium. FIG. 20Cshows both left atrial member 184 and right atrial member 186 in placefor apposing PFO tissues. In one embodiment, left atrial member 184 maybe rotated (curved arrow) to move the hooked portion along the leftatrial surface of the PFO to apply energy at multiple locations.

Referring to FIG. 21A, one embodiment of a backstop catheter device 800for treating a PFO may include an outer catheter element 802, an innercatheter element 804, a backstop 806 coupled with a portion 808extending through the inner shaft 804, and energy delivery arms 810.Energy delivery arms 810 can include ultrasound transducers, microwaveantennae, or RF electrodes. The backstop catheter device 800 is advancedthrough the PFO and used to help advance an energy delivery catheter tothe right atrial side of the PFO. Relative translation of an inner 804and outer catheter element 802 deploy a set of arms 810 which carry theenergy delivery elements. The energy delivered breaks down the collagenin each part of the PFO, and allows the tissues to be welded together.The energy delivered could take the form of RF, microwave, orultrasound. RF energy can either be monopolar, in which the backstop 806is electrically insulated such that it is not part of the energydelivery path, or bipolar, in which case the backstop 806 acts as theenergy return electrode. If desired, the inner catheter 804 of theenergy delivery catheter 800 can be used to infuse liquid albumin to actas a protein solder for the system. Alternatively, the shaft of thebackstop 806 could be covered with a tube of solid or braided materialmade of, or soaked in, a tissue solder. After delivery of the energy andactivation and bonding of the tissue solder to the PFO walls, thebackstop 806 is withdrawn through the PFO and the entire system iswithdrawn.

As illustrated in FIG. 21B, in another embodiment, a catheter device 820can include an expandable balloon member 822 and an expandable backstop824. The balloon catheter 820 can be outfitted with sections 826 ofpiezo film/foil which can be driven electrically to produce anultrasound signal to heat and seal a PFO. The balloon member 822 andexpandable backstop 824 are used to position the catheter device 820 inthe desired location and energy is then applied via the piezo film/foil826 for treating the PFO.

In other embodiments, PFO closure systems according to the presentinvention may utilize one or more clips to close the PFO. Such systemscan be divided into designs that involve both a right and left atrialcomponent, and those that are right-sided only. While they are generallynot energized, it may be desirable to add energy to any of these designsto facilitate adhesion and sealing.

Referring now to FIG. 22A through FIG. 22D, another embodiment of thepresent invention is described which includes a catheter device 832comprising a coil closure device 830. According to this embodiment, acatheter 832 is used to insert a closure device 830 comprising a pair offlexible, pre-formed coils 834, 836 into both the left and rightatriums. The spring tension in the pair of coils 834, 836 pulls theprimum into the secundum to close the PFO.

Referring now to FIG. 23, another embodiment of the present inventionincludes a deployable spring coil closure device 840 which may insertedthrough a small pierced hole in the septum. For example, a needle tippedcatheter (not shown) can be used to pierce the primum and install thespiral spring coil 840 (e.g., similar to that described above) through asmall hole made in the septum rather than through the PFO tunnel itself.

Referring now to FIG. 24, in another embodiment, a spiral spring coil850 is inserted through the PFO. The portion 852 of the wire form thatgoes through the actual PFO tunnel is shaped to maximize contact areaand flatten the PFO by stretching it closed. RF energy is then appliedto the wire 850 to bum it into the tissue and promote tissue growth,especially in the area between the primum and secundum where there is ahigh contact area. The flattened PFO combined with tissue healing onadjacent primum and secundum sides might cause the PFO to heal closed.The spring tension provided by the spiral spring coil 850 will keep thePFO closed as the tissue heals. The tissue healing around the wire 850will help secure it to the tissue and prevent embolization.

In another embodiment, a patch might also be used on the right atrialside to provide an additional means to seal the PFO. If it is desirableto prevent the wire around the patch area from receiving RF energy, itis possible to electrically insulate the portion of the wire that is notdesired to burn into the tissue (not shown). In another embodiment, the“zig zag” portion 852 of the coil 850 located in the flattenedpassageway between the primum and secundum might have sharp features(such as needles or barbs) which cause the adjacent surfaces of theprimum and secundum to bleed and heal together. RF energy might be usedin any of the embodiments of the spiral spring coil described above toburn some or all of the device into the tissue and promote rapid healingand prevent embolization.

Although the foregoing description is complete and accurate, itdescribes only exemplary embodiments of the invention. Various changes,additions, deletions and the like may be made to one or more embodimentsof the invention without departing from the scope of the invention.Additionally, different elements of the invention could be combined toachieve any of the effects described above. Thus, the description aboveis provided for exemplary purposes only and should not be interpreted tolimit the scope of the invention as set forth in the following claims.

1. A catheter device for treating a patent foramen ovale in a heart, thecatheter device comprising: an elongate catheter body having a proximalend and a distal end; at least one tissue apposition member at or nearthe catheter body distal end for bringing tissues adjacent the patentforamen ovale at least partially together; and at least one energytransmission member at or near the distal end for applying energy to thetissues to substantially close the patent foramen ovale acutely.
 2. Acatheter device as in claim 1, wherein the at least one tissueapposition member comprises at least a first tissue apposition memberfor contacting tissue adjacent the patent foramen ovale from a rightatrium of the heart.
 3. A catheter device as in claim 2, wherein the atleast one tissue apposition member further comprises at least a secondtissue apposition member for contacting tissue adjacent the patentforamen ovale from the right atrium.
 4. A catheter device as in claim 3,wherein the first and second tissue apposition members compriseopposable jaws, and wherein at least one of the first and second membersis advanceable through tissue adjacent the patent foramen ovale.
 5. Acatheter device as in claim 4, wherein the first apposition memberadvances through septum secundum tissue and the second apposition memberadvances through septum primum tissue.
 6. A catheter device as in claim2, wherein the at least one tissue apposition member further comprisesat least a second tissue apposition member for advancing through thepatent foramen ovale to contact the tissues from a left atrium of theheart.
 7. A catheter device as in claim 6, wherein at least one of thefirst and second tissue apposition members comprises an expandablemember.
 8. A catheter device as in claim 7, wherein both the first andsecond tissue apposition members comprise expandable members, andwherein at least one of the expandable members is slidably disposedalong the catheter body so as to be axially movable toward the otherexpandable member.
 9. A catheter device as in claim 7, wherein at leastone expandable member includes at least one aperture for releasingconductive fluid to contact the tissues.
 10. A catheter device as inclaim 9, wherein at least one expandable member includes a plurality ofsmall apertures for releasing the conductive fluid.
 11. A catheterdevice as in claim 9, wherein one of the first and second memberscomprises an expandable member and the other of the first and secondmembers comprises a deployable shaped portion, wherein the expandablemember and the shaped portion are brought together to bring the tissuestogether.
 12. A catheter device as in claim 11, wherein the deployableshaped portion comprises a shape memory material that changes from anundeployed to a deployed shape when released from the catheter body. 13.A catheter device as in claim 6, wherein the first and second tissueapposition members comprise a clamp for clamping the tissues together.14. A catheter device as in claim 6, wherein the first tissue appositionmember has a first deployed shape and the second tissue appositionmember has a second deployed shape, and wherein the first and secondmembers, when deployed to contact the tissues, cause the tissues to bebrought together.
 15. A catheter device as in claim 14, wherein thefirst shape comprises approximately a curved hook for curving over anedge of the patent foramen ovale to apply force to the tissues from theleft atrium, and wherein the second shape comprises approximately astraight, linear shape for applying pressure to the tissues from theright atrium.
 16. A catheter device as in claim 6, wherein the first andsecond tissue apposition members comprise magnets having oppositepolarity.
 17. A catheter device as in claim 6, wherein the first tissueapposition member comprises a pair of opposable jaws for contacting theseptum secundum from the right atrium, and the second tissue appositionmember comprises a curved member for advancing through the patentforamen ovale to contact the septum primum from the left atrium.
 18. Acatheter device as in claim 1, wherein the at least one tissueapposition member comprises: at least two tissue apposition members formoving relative to one another to bring the tissues together betweenthem; and at least one biasing member for biasing the tissue appositionmembers toward a first side of the patent foramen ovale.
 19. A catheterdevice as in claim 18, wherein the tissue apposition members are movablealong the patent foramen ovale from the first side to a second oppositeside of the patent foramen ovale.
 20. A catheter device as in claim 19,wherein the catheter body has a cross-sectional shape such that when thetissues are brought together between the two tissue apposition members,the tissues urge the catheter body to a different position relative tothe patent foramen ovale.
 21. A catheter device as in claim 20, whereinthe shape is selected from the group consisting of triangular, oval,elliptical and diamond shaped.
 22. A catheter device as in claim 20,wherein the two tissue apposition members comprise: one shape-memorytissue apposition member; and one jaw member.
 23. A catheter device asin claim 20, further comprising at least one aperture on the catheterbody for releasing one or more fluids to enhance the application ofenergy to the tissues to close the patent foramen ovale.
 24. A catheterdevice as in claim 20, further comprising a coating over the catheterbody, the coating enhancing application of energy to the tissues whenthe tissues contact the catheter body.
 25. A catheter device as in claim1, wherein the at least one tissue apposition member comprises anexpandable member releasably disposed within the catheter body, whereinadvancing the expandable member out the distal end of the catheter bodyor retracting the catheter body relative to the expandable member allowsthe expandable member to expand within the patent foramen ovale.
 26. Acatheter device as in claim 25, wherein the expandable member comprisestwo prongs that expand apart to provide lateral force to the tissuesadjacent the patent foramen ovale.
 27. A catheter device as in claim 26,wherein the prongs do not extend into the left atrium of the heart. 28.A catheter device as in claim 26, wherein the prongs are spring loaded.29. A catheter device as in claim 26, wherein the prongs comprise ashape memory material.
 30. A catheter device as in claim 26, wherein theprongs include at least one vacuum aperture for applying vacuum force tofurther bring the tissues together.
 31. A catheter device as in claim 1,further comprising a guide member for advancing through the patentforamen ovale, wherein the catheter device is slidably disposed over theguide member.
 32. A catheter device as in claim 31, wherein the guidemember comprises a guidewire divided along a portion of its length, thedivided portion comprising expandable shape memory material.
 33. Acatheter device as in claim 31, wherein the guide member comprises atleast one tip for contacting a left atrial surface of the tissuesadjacent the patent foramen ovale.
 34. A catheter device as in claim 33,wherein the at least one tip is conformable to the left atrial surface.35. A catheter device as in claim 33, wherein the guide member isretractable to engage the at least one tip with the left atrial surface.36. A catheter device as in claim 31, wherein the guide member comprisesat least one of the energy transmission member(s).
 37. A catheter deviceas in claim 36, wherein the guide member comprises an expandable memberfor expanding within the patent foramen ovale, and wherein theexpandable member comprises at least one radiofrequency energytransmission member.